The present invention relates to an electronic circuit which is operated in synchronization with a clock. More particularly, it relates to a semiconductor integrated circuit which is operated in synchronization with a clock and to a technology which is effective when applied to an information processing apparatus represented by, e.g., a microcomputer.
Among semiconductor integrated circuits which are operated in synchronization with clocks such as microcomputers, there are some which generate synchronous clock signals only through internal oscillation without using externally mounted crystal oscillators. Patent Document 1 discloses a microcomputer which generates a synchronous clock signal only through internal oscillation without using an externally mounted crystal oscillator. Patent Document 2 discloses a circuit for trimming the oscillation frequency of an internal oscillator which conducts internal oscillation without using an externally mounted crystal oscillator.
[Patent Document 1] Japanese Unexamined Patent Publication No. Hei 11(1999)-510938
[Patent Document 2] Japanese Unexamined Patent Publication No. Hei 10(1998)-187273